Locking device



March 29, 1960 Y FANSMITH 2,930,219

' I LOCKING DEVICE Filed June 6, 1957 INVENTOR John F. Fansmith UnitedStates Patent 2,930,219 LOCKING DEVICE John F. Fansrnith, FranklinTownship, Allegheny County, Pa.

Application June 6, 1957, Serial No, 663,942 4 Claims. c1. 70-4zs' lockin open position the master switch conducting electric current to themachinery so that current cannot flow to the machinery until the lockingdevice is removed and the master switch is closed; but the lockingdevicemayalso be otherwise applied, as, for example, to an enclosurecontaining the machinery or to an enclosure containing the master switchbarring entrance to the enclosure until the locking device has beenremoved.

Machinery may be worked on or serviced by a number of different workmenor by workmen of anumber of different crafts whose work is beingconducted more or less at the same time. For example, a machinist, anelectrician and a painter may be working on or about a particularmachine doing work which may extend over a. substantial period of time.It is importantthat the machine be not operated until all of the workmenhave completed their work and the machine is in fully oper' ativecondition and the workmen have removed their tools and are out of thevicinity of the machine. I

Simply providing each workman or a workman of each craft with anordinary padlock to apply to the master switch of the machine does notinsure against operation of the machine before all of the workmen havecompleted their work. For example, on a particu lar day the threeworkmen above mentioned, the machinist, the electrician and the painter,may all be working on the machine. Assume that the painter arrived firstandapplied'his lock to the master switch of the machine. There isprovision in the master switch for receiving only one lock so theworkmen arriving later cannot apply their locks. Assume that the painteris the first to finish. He removes his lock and goes away. He issupposed to notify the machinist and the electrician that he has removedhis lock, but he forgets, or at least omits to do so. There is noassurance against operation of the machine before the machinist and theelectrician have completed their work. An'operator seeing the masterswitch unlocked may think that all the workmen have finished their workand start the machine, injuring the and/or damaging the machinist and/orthe electrician machine. p

I provide a locking device providing a definite safeguard against theoperation. of. a machine until all of the workmen Working on the machinehave completed their work. Each workman or a workman of each craft isprovided with one'of my locking devices andas he goes to work on the.machine he applies his locking device, the locking. devices beingconstructed and arranged to be applied in series so that application ofeach locking device prevents operation of the machine and 2 V preventsremoval o'f'all previously applied locking def vices. The lockingdevices must be removed in the inverse order of their application.

My locking device comprises a key-operated locking member having akeyhole and a cover operatively positionable to render thekeyholeinaccessible and removable to inoperative position to render thekeyhole accessible, the locking, device having means for receivinganother locking member. to lock the cover in operative positionrendering the keyhole inaccessible. When a second workman goes on thejob a second locking member is applied to said means whereby to lock thecover in operative position, and any number of similar locking devicesmay be applied in series one after the other.

Preferably the, cover is mounted on the locking mem her for movementbetween an operative position rendering the keyhole inaccessible and aninoperative position rendering the keyhole accessible. I prefer toslidably mount the cover on the locking member for. 'sliding movementbetween said positions. The cover preferably has means for receivinganother locking member to lock the cover in operative position renderingthe keyhole inaccessible. i r

The key-operated locking member preferably has means forming a retainerand guide for the slidable cover and the cover is preferably mounted inthe retainer and guide for sliding'r'novement. between operative andinoperative positions. member and cover have gcooperating, meanslimiting movement of the cover in one direction in the retainer andguide, the cover when in its extreme position in that direction being inoperative position, the locking device having means for receivinganother locking member to hold the cover against substantial movement inthe opposite direction and thereby maintain the cover in operativeposition. In my preferred structure. I provide the cover with an openingthrough which access. to the keyhole may be had when the cover is ininoperative position, which opening is moved to a position offset fromthe keyhole when the cover is inoperative posi-.

tion. The cover may have a second opening adapted ,when; the cover is inoperative position to receive. an-

other locking member 'to'hold the cover in that position.

I also desirably provide means limiting movement of the cover in thedirection away from its. operative position to prevent inadvertentseparation of thecover from the locking member.

Q'ther details, objects and advantages off the invention' will becomeapparent as the following description of a present preferred embodimentthereofproceeds.

In the accompanying drawings I have shown a, present preferredembodiment of the invention in which Figure l is a front. view of akey-operated locking member forming a portion of my locking device;

Figure 2 is a side View of the key-operated locking member shown inFigure 1;

Figure 3 is a bottom view of the keyoperated lockingmember shown inFigures 1 and 2;

Figure 4 is a face view of a cover used with the key-operated lockingmember shown in Figures 1, 2 nd 3 and adapted tobe slidably appliedthereto; and

Figure 5 is a view showing two, of my locking devices in series; andillustrating-how their employment positively. V prevents operationof;machinery until all-workmen work' ing on the, machinery have completed,their work.

Referring now more particularly to the drawings, while my key-operatedlocking member may take various forms it is shown in the drawings as. inthe form of a padlock- '2 having a body 3 and a shackle 4. The padlockmay, exceptfor the provision for application of the cover Patented Mar.29, 196.0

Desirably the locking presently to be described, be of conventionalconstruction having in its bottom a keyhole through which a key isadapted to be inserted to operate the lock cylinder to open the shackle.The lock, cy1inder may be of any desired construction and the shacklemay be either of the pivoted type or of the sliding type. Since all ofthe portions of the padlock described up to this point may beconventional they are not shown in detail.

Disposed at the bottom of the body 3 of the padlock 2 are opposedextensions 6 each extending along about three-fourths of the length ofthe body of the padlock as shown in Figures 1 and 3 and each having aninward foot 7 as shown in Figure 2 whereby to form a retainer and guide,designated generally by reference numeral 8, for a cover designatedgenerally by reference numeral 9. The cover has a body 10 shaped to bereceived and slidably guided in the retainer and guide 8, the body 10having therein a first opening 11 and a second opening 12. At one end ofthe body 10 are opposed lateral projections 13 adapted when the cover 9moves in the retainer and guide 8 toward the right viewing Figures 3 and4 to engage the left-hand ends viewing Figures 1 and 3 of the opposedextensions 6, thus limiting movement of the cover relatively to the body3 of the padlock in that direction. The cover 9 has at its left-hand endviewing Figure 4 a recess 14 and the lock body 3 has a pin 15, appliableafter insertion of the cover 9 into the retainer and guide 8, whichlimits movement of the cover toward the left; when the pin 15 seats inthe body of the recess 14 the cover is in inoperative position with theopening 11 in the cover inalignment with the keyhole 5 so as to providefor access to the keyhole through the'opening 11 by a key whereby thepadlock may be unlocked.

When the locking device is' applied, as to the master switch of amachine, and is in closed or locked position maintaining the masterswitch open and a second workman comes to work on the same machine heapplies his locking device in series with the first locking device. Hedoes that by moving the cover 9 of the first locking device to the rightuntil the opening 12 thereof is in the clear at the side of the body 3.At that time the cover is in operative position as the opening 11 isofiset from the keyhole 5 and the body 10 of the cover 9 between theopening 11 and the recess 14 is in line with or covers the keyholepreventing access thereto by a key. The second workman passes theshackle of his key-operated locking member or padlock through theopening 12 and locks his padlock. The padlock of the second Workmanmaintains the cover 9 of the first locking device in operative positionuntil the second padlock has been removed. Similarly a third, fourth,etc., locking device may be applied in series, one by each additionalworkman who comes to work on the machine, and the machine cannot beoperated until all of the padlocks have been removed. the removal beingby necessity in the inverse order of application of the padlocks. InFigure 5 the first padlock 2 is shown applied to a switch box 17 to lockthe same closed with its cover 9 in operative position rendering thekevhole of that padlock inaccessible and the second padlock 2' is shownwith its shackle 4' in the opening 12 of the cover 9 of the firstlocking device, positively rendering the keyhole of the first padlockinaccessible, and with its cover 9' in inoperative position renderingthe keyhole of the second padlock accessible by a key 16.

While I have shown and described a present preferred embodiment of theinvention it is to be distinctly understood that the invention is notlimited thereto but may be otherwise variously embodied within the scopeof the following claims. 7

I claim:

1. A locking device comprising a key-operated locking member, saidmember having a keyhole and having means forming a retainer and guidefor a slidable cover, and a cover mounted in the retainer and guide forsliding movement between an operative position rendering the keyholeinaccessible and an inoperative position rendering the keyholeaccessible, the cover having therein a first opening through whichaccess to the keyhole may be had when the cover is in inoperativeposition, the locking member and cover having cooperating means limitingmovement of the cover in one direction in the retainer and guide, thecover when in its extreme position in that direction being in operativeposition with the first opening in the cover otfset from the keyhole,the cover having therein a second opening adapted when the cover is inoperative position to receive another locking member to hold the coveragainst substantial movement in the opposite direction and therebymaintain the cover in operative position.

2. A locking device comprising a key-operated locking member, saidmember having a keyhole and having means forming a retainer and guidefor a slidable cover, a cover mounted in the retainer and guide forsliding movement between an operative position rendering the keyholeinaccessible and an inoperative position rendering the keyholeaccessible, the cover having therein a first opening through whichaccess to the keyhole may be had when the cover is in inoperativeposition, the locking member and cover having cooperating means limitingmovement of the cover in one direction in the retainer and guide, thecover when in its extreme position in that direction being in operativeposition with the first opening in the cover offset from the keyhole,the cover having therein a second opening adapted when the cover is inoperative position to receive another locking member to hold the coveragainst substantial movement in the opposite direction and therebymaintain the cover in operative position, and means limiting movement ofthe cover in said opposite direction when the second mentioned lockingmember is removed from the second opening whereby to prevent inadvertentseparation of the cover from the first mentioned locking member.

3. A locking device comprising a padlock comprising a casing havingtherein a keyhole for receiving a key to operate the padlock, the casingbeing formed to provide a guideway for a slidable cover, and a coverslidably received in the guideway, the cover having laterally projectingmeans adjacent an end thereof limit ing by engagement with a portion ofthe casing slidable movement of the cover toward its opposite end, thecover when in its extreme position toward said opposite end covering andrendering inaccessible the keyhole, and locking means cooperating withsaid opposite end of the cover preventing the cover from sliding towardits first mentioned end.

4. A locking device as claimed in claim 3 in which the cover has akeyhole therethrough positioned to be aligned with the keyhole of thepadlock so that a key may be inserted through the keyhole in the coverand into the keyhole of the padlock to unlock the padlock when the coveris moved somewhat toward its first mentioned end from its said extremeposition.

References Cited in the file of this patent UNITED STATES PATENTS GreatBritain Nov. 7, 1916

